Facile template free approach for the large-scale solid phase synthesis of nanocrystalline XIn2S4 (X = Cd/Zn) and its photocatalytic performance for H2 evolution

In the present study, we have demonstrated a unique approach for the synthesis of nanostructured ternary metal sulphides, XIn2S4(X = Cd, Zn), using a simple, template free and low temperature solid phase reaction. A stoichiometric amount of precursors including CdO/ZnO, In(2)O(3)and thiourea were mixed homogeneously and heated at 150 degrees C for different time intervals to produce nanostructured XIn2S4. Various molar ratios of the precursors were tried and among the different ratios, the molar ratio of 1 : 1 : 8 was found to be optimum for the growth of phase pure nano crystalline XIn2S4. X-ray analysis confirms the formation of cubic spinel Cadmium Indium Sulfide (CdIn2S4) and hexagonal Zinc Indium Sulfide (ZnIn2S4). HRTEM analysis confirms the formation of nanostructures of XIn(2)S(4)with spherical and rod like mixed morphology. The band gap of the as synthesized materials is within the visible regioni.e.2.25 and 2.6 eV for CdIn(2)S(4)and ZnIn2S4, respectively. Therefore, the activity of both the photocatalyts was tested for hydrogen generation by H2S and H2O splitting under natural solar light. The ZnIn(2)S(4)photocatalyst was found to be more active for both H2S and H2O splitting reactions with H(2)evolution rates of 6994 mu mol h(-1)g(-1)and 243 mu mol g(-1), respectively, whereas for CdIn(2)S(4)the rates were found to be 6128 mu mol h(-1)g(-1)and 128.4 mu mol g(-1), respectively. The H(2)evolution rate by H2S splitting was found to be much higher than various previously reported nanostructured photocatalysts. The simple, environmentally friendly and cost effective method reported herein can be applied for the large scale synthesis of XIn(2)S(4)nanoparticles, which is the novelty of the present work.